textproduct: Albany

WHAT HAS CHANGED

Guidance continues to suggest rain changing to snow across high terrain for late Thursday into Thursday night. Some valley areas may see a brief changeover to snow Friday morning, but model guidance is in fairly good agreement that any accumulation is minor in valley areas and will be mainly limited to grassy surfaces.

KEY MESSAGES

1) An early season accumulation of wet snow is likely across higher terrain areas later today into Friday thanks to a storm system passing to the south, which could allow for some slippery travel. A brief period of snow is possible for valley areas on Friday morning, but accumulation looks minor and limited to mostly grassy surfaces.

DISCUSSION

KEY MESSAGE 1...

An area of low pressure is currently located over the Ohio Valley. Widespread clouds have already overspread the region and moisture is increasing. Some light rain will be developing by around daybreak and a steady rain will be in place over much of the region by the mid to late morning hours. With isentropic lift in place, steady light to moderate rainfall is expected through the day with the heaviest totals across the Catskills. Temperatures will be steady during the morning hours (ranging from the mid 30s over the Adirondacks to the mid 40s elsewhere) but will be falling during the afternoon hours. Dynamic cooling and wet-bulbing will allow precip to start to change over to snow by late today over the Adirondacks, with a dusting across the highest terrain by this evening.

The area of low pressure will be passing by to the south across the northern mid Atlantic States for tonight and will be reaching the NYC Metro area by Friday morning. As this occurs, the low-level flow out of the north will be allowing some colder temps to filter in at low levels. Temps aloft will continue to slowly cool as well, as the large upper level trough to the west moves closer to the area. With steady precip still ongoing, more and more of the high terrain will be changing over from rain to snow, including the eastern Catskills and southern Greens of southern VT. Valley areas will be falling into the 30s as well.

On Friday morning, the low pressure area will be passing close to Long Island and southern New England. Deformation on the northwest side of the storm will continue to allow for some steady precip into the morning hours and some mesoscale models suggests that some banding of precip is possible as well. As this occurs, even valley areas may briefly change over to snow, although any accumulation will generally be light (about an inch or less) and mainly limited to colder surfaces, like grassy areas. Mesoscale models, including the new RRFS and 3km HRRR, as suggested this possibility, but have had little run to run consistency on where any banding may be, the exact timing and snowfall amounts.

There remains some uncertainty in the guidance, such as how long precip lingers through the day on Friday, where any banded precip may be and just how much snowfall occurs for the high terrain areas. As of now, NBM probabilities suggests that only small parts of the highest terrain of the Adirondacks, Catskills and Greens may exceed 4" of snow, as there is a 40-70% chance for some the highest peaks. NBM suggest that most high terrain areas look to top out in the 1-3" range. Valley areas have a fairly low probability to exceed 1", with most valley areas under a 25% chance to get over an inch at this time. WSSI shows the most likely category for the highest terrain is "Minor Impacts" at this time, with slippery travel being the main impact. Will continue the Winter Weather Advisory for the eastern Catskills, southern Adirondacks and southern Greens into Friday morning, with slippery travel being the main threat at this time.

Precip should be tapering off to snow showers and flurries by late Friday. Some additional flurries are possible Friday night into Saturday with the upper level trough still overhead, but no additional accumulation is expected. Some lake effect is also possible by later in the weekend, but this looks primarily west of the region thanks to the north to northwest flow in place.

AVIATION /06Z THURSDAY THROUGH MONDAY/

Through 06z Friday...As of 12:25 AM EST, flying conditions remain VFR at all terminals, although some scattered light showers have already developed over the region. Mainly VFR conditions expected through the next few hours, but showers gradually increase in coverage and develop into steady light rain during the pre-dawn hours to shortly after sunrise. MVFR vsbys possible within these showers, and cigs should also begin to trend down to MVFR as well, especially by 11-13z. Light rain with MVFR vsbys and cigs expected through the morning, but by early afternoon we may see areas of moderate rain with vsbys/cigs trending down to IFR. ALB/GFL likely the first terminals to drop to IFR, but low confidence in exact timing. Higher confidence for deterioration to IFR vsbys/cigs at all terminals as we head past sunset this evening. IFR vsbys/cigs and rain continue through the end of the TAF period, with some wet snow mixing in towards the end of the TAF period at GFL and possibly PSF.

Winds are currently light and variable, but will increase to around 10 kt from the N/NE through the morning, with some gusts of 15-20 kt this afternoon. Winds shift more to the north after sunset, but remain at around 10 kt with gusts 15-20 kt through the end of the TAF period.

Outlook...

Friday Night: No Operational Impact. NO SIG WX. Saturday: No Operational Impact. NO SIG WX. Saturday Night: No Operational Impact. NO SIG WX. Sunday: No Operational Impact. NO SIG WX. Sunday Night: No Operational Impact. NO SIG WX. Monday: No Operational Impact. NO SIG WX. Monday Night: No Operational Impact. NO SIG WX. Tuesday: No Operational Impact. NO SIG WX.

ALY WATCHES/WARNINGS/ADVISORIES

CT...None. NY...Winter Weather Advisory from 10 AM this morning to 10 AM EST Friday for NYZ033-042. Winter Weather Advisory from 7 PM this evening to 1 PM EST Friday for NYZ058-063. MA...None. VT...Winter Weather Advisory from 10 AM this morning to 10 AM EST Friday for VTZ013-014.